Plugin Editor: Disable the documentation look up button when no function is selected.

Props xkon.
Fixes #41143.


Built from https://develop.svn.wordpress.org/trunk@44617


git-svn-id: http://core.svn.wordpress.org/trunk@44448 1a063a9b-81f0-0310-95a4-ce76da25c4cd

Author: pento

wp-admin/js/theme-plugin-editor.js

@@ -53,6 +53,8 @@ wp.themePluginEditor = (function( $ ) {
 		component.textarea = component.form.find( '#newcontent' );
 		component.textarea.on( 'change', component.onChange );
 		component.warning = $( '.file-editor-warning' );
+		component.docsLookUpButton = component.form.find( '#docs-lookup' );
+		component.docsLookUpList = component.form.find( '#docs-list' );
 
 		if ( component.warning.length > 0 ) {
 			component.showWarning();
@@ -77,6 +79,15 @@ wp.themePluginEditor = (function( $ ) {
 			}
 			return undefined;
 		} );
+
+		component.docsLookUpList.on( 'change', function() {
+			var option = $( this ).val();
+			if ( '' === option ) {
+				component.docsLookUpButton.prop( 'disabled', true );
+			} else {
+				component.docsLookUpButton.prop( 'disabled', false );
+			}
+		} );
 	};
 
 	/**